Laser tool for removing scaling

ABSTRACT

An example laser tool includes a laser head to output a laser beam and a robotic arm that is articulated and that is connected to the laser head. The robotic arm includes segments that are connected by flexible joints to enable movement of the laser head in six degrees of freedom. A control system is configured to control the robotic arm to direct output of the laser beam.

CROSS-REFERENCE

This application is a divisional application of U.S. patent applicationSer. No. 16/141,721 filed Sep. 25, 2018.

TECHNICAL FIELD

This specification relates generally to example laser tools for removingscaling from objects, such as metal pipes.

BACKGROUND

Scaling includes deposits of inorganic material that coat metal pipesand other objects. Scaling can be caused by a chemical reaction, achange in pressure and temperature, or a change in composition of asolution within a pipe. A build-up of scaling can decrease the flow offluid through a pipe or completely block the flow of fluid. This can beproblematic, particularly in cases where the pipes are locatedunderground and, therefore, are not easily accessible.

SUMMARY

An example laser tool includes a laser head to output a laser beam and arobotic arm that is articulated and that is connected to the laser head.The robotic arm includes segments that are connected by flexible jointsto enable movement of the laser head in six degrees of freedom. Acontrol system is configured to control the robotic arm to direct outputof the laser beam. The laser tool may include one or more of thefollowing features, either alone or in combination.

The laser tool may include a laser source to generate the laser beam andfiber optics through which the laser beam passes to reach the laserhead. At least part of the fiber optics may be within the robotic arm.The control system may include a computing system located remotely fromthe laser tool. A stabilizer may secure part of the robotic arm againsta structure within a confined space. The stabilizer may include a holderto contain the robotic arm and support arms connected to the holder. Thesupport arms may be controllable move to relative to the robotic arm.Pads may be connected to the support arms. The support arms may becontrollable to move the pads so that the pads contact a surface of theconfined space to maintain the holder at set position within theconfined space.

The laser tool may include an elongated structure configured to mount tothe robotic arm. The elongated structure may be configured forconnection to a device for lowering the laser tool into a wellbore.

The laser tool may include one or more sensors to sense environmentalconditions in a region where the laser tool operates. The one or moresensors may be configured to provide data based on the environmentalconditions to the control system. The control system may be configuredto use the data to affect operation of the laser tool. The sensors mayinclude one or more of a temperature sensor to sense temperature and anacoustic sensor to sense sound. The sensors may include an acousticcamera configured to obtain data based on acoustics in the region wherethe laser tool operates.

The laser tool may include one or more head purging nozzles locatedinside the laser head. The head purging nozzles may be configured tooutput a purging medium within the laser head. The laser tool mayinclude one or more target purging nozzles located outside the laserhead. The target purging nozzles may be configured to output a purgingmedium towards a target of the laser beam.

The laser tool may include an optical assembly within the laser head toshape the laser beam prior to output and a vacuum connected to therobotic arm. The vacuum may be configured to suction material away fromthe laser head. An optical power of the laser beam may be between 1kilowatt (kW) and 10 kW.

An example method of removing scaling from an object within a confinedspace uses a laser tool having a robotic arm and a laser head connectedto the robotic arm to output a laser beam. The object may be a metalpipe. The confined space may be an interior of the metal pipe. Themethod includes moving the laser tool into the confined space andcontrolling the robotic arm to move in at least three degrees of freedomwithin the confined space in order to direct a laser beam to remove thescaling from the object. The method may include one or more of thefollowing features, either alone or in combination.

Controlling the robotic arm may include controlling the robotic arm tomove in at least four degrees of freedom, to move in at least fivedegrees of freedom, or to move in six degrees of freedom. Controllingthe robotic arm may include moving the robotic arm in a spiral patternor in a circular pattern. Directing the laser beam for removal of thescaling may include pointing the laser beam at the scaling or pointingthe laser beam at a surface of the object adjacent to the scaling. Thescaling removed from the object may be suctioned away from the laserhead using a vacuum. The method may include outputting a purging mediumtowards the scaling during removal of the scaling by the laser tool.

The method may include monitoring environmental conditions within theconfined space during removal of the scaling by the laser tool. Controlover the robotic arm may be based at least in part on the environmentalconditions. The environmental conditions may include one or more atemperature within the confined space, pressure within the confinedspace, or sound within the confined space.

The method may include securing at least part of the robotic arm againstthe object during removal of the scaling. The at least part of therobotic arm may be centered within the confined space during removal ofthe scaling,

An optical power of the laser may be between 1 kilowatt (kW) and 10 kW.The laser beam may be shaped prior to output. Shaping the laser beam mayinclude at least one of focusing the laser beam, collimating the laserbeam, or dispersing the laser beam.

Any two or more of the features described in this specification,including in this summary section, may be combined to formimplementations not specifically described in this specification.

At least part of the tools and processes described in this specificationmay be controlled by executing, on one or more processing devices,instructions that are stored on one or more non-transitorymachine-readable storage media. Examples of non-transitorymachine-readable storage media include read-only memory (ROM), anoptical disk drive, memory disk drive, and random access memory (RAM).At least part of the tools and processes described in this specificationmay be controlled using a data processing system comprised of one ormore processing devices and memory storing instructions that areexecutable by the one or more processing devices to perform variouscontrol operations.

The details of one or more implementations are set forth in theaccompanying drawings and the description subsequently. Other featuresand advantages will be apparent from the description and drawings, andfrom the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an example laser tool within the cross-sectionof a metal pipe targeting scaling directly with a laser beam.

FIG. 2 is a block diagram showing six degrees of freedom and the examplelaser tool superimposed over the block diagram.

FIG. 3 is a side view of the example laser tool coupled with a vacuumwithin the cross-section of a metal pipe.

FIG. 4 is a flow chart of an example process for removing scaling froman object using the example laser tool.

FIG. 5 is a side view of the example laser tool within the cross-sectionof a metal pipe targeting the metal pipe with the laser beam to removescaling.

Like reference numerals in different figures indicate like elements.

DETAILED DESCRIPTION

Described in this specification are example laser tools for removingscaling from objects, such as metal pipes, and example methods forremoving scaling using those tools. An example laser tool includes alaser head to output a laser beam. The laser beam may be generatedlocally or remotely and transmitted to the laser head. The laser toolincludes a robotic arm that is articulated and that is connected to thelaser head. The robotic arm includes segments that are connected byflexible joints to enable movement of the laser head in six degrees offreedom. This movement enables the laser tool to treat scaling fromvarious angles and to apply the laser beam to the scaling in variouspatterns, such as circles or spirals.

When applied directly to the scaling, the laser beam removes scalingthrough sublimation, spallation, or both. Sublimation includes changingscaling from a solid phase directly into a gaseous phase without firstchanging into a liquid phase. Spallation includes breaking the scalinginto small pieces. The laser tool may also target areas adjacent to thescaling to cause those areas to expand and the scaling to detach as aresult. A control system controls the robotic arm to direct output ofthe laser beam based on factors such as the extent of the scaling, thelocation of the scaling, and environmental conditions in a region to betreated.

FIG. 1 shows an example implementation of a laser tool of the typedescribed in the preceding paragraphs. Laser tool 10 includes a laserhead 11. Laser head 11 is configured to receive a laser beam from asource and to output the laser beam 13. Laser head 11 may house anoptical assembly. The optical assembly includes optics, such as mirrors,lenses, or both mirrors and lenses to direct the laser beam, to shapethe laser beam, and to size the laser beam. For example, the opticalassembly may include one or more lenses to focus the laser beam, tocollimate the laser beam, or to spread the laser beam to cause the laserbeam to diverge.

In a collimated laser beam, the laser beam maintains a constantcross-sectional area as it propagates. The power intensity of acollimated laser beam is also typically constant. Collimated laser beamsmay be most appropriate for penetrating blockages or other scalingdeposits that completely block a pipe or other object. A focused laserbeams decreases in cross-sectional area as it propagates to provide anincreased power intensity at its focal point. Focused laser beams may bemost appropriate for addressing small accumulations of scaling thatrequire additional energy to dislodge. A divergent laser beam increasesin cross-sectional area as it propagates. Divergent laser beams may bemost appropriate for spreading heat over the entire surface of a scalingdeposit.

Laser head 11 is connected to robotic arm 14. Robotic arm 14 isarticulated and includes segments that are connected by flexible jointsto enable movement of the laser head. Examples of segments includesegments 16 and 17. Adjacent segments have complementary matingmechanisms to allow connection in series. In some implementations, thesegments are connected to enable movement of the laser head in sixdegrees of freedom. In Cartesian XYZ space, the six degrees of freedominclude: (1) moving forward and backward on the X-axis, (2) moving leftand right on the Y-axis, (3) moving up and down on the Z-axis, (4)tilting side-to-side over the X-axis, (5) tilting forward and backwardover the Y-axis, and (6) tilting left and right over the Z-axis. Thesesix degrees of freedom are known as surge, sway, heave, roll, pitch, andyaw, respectively. FIG. 2 uses arrows to show potential movements oflaser tool 10 (shown in dashed lines) along the surge 20, sway 21, heave22, roll 23, pitch 24, and yaw 25 degrees of freedom. The robotic arm isalso rotatable about its longitudinal axis (the X-axis of FIG. 2) asrepresented by arrow 27 of FIG. 1.

Movement of individual segments may be controlled using motors orhydraulics. For example, each segment may include a motor and associatedelectronics. The electronics may be configured to receive commands froma control system and to control operation of the motors based on thecommands.

The robotic arm is modular in the sense that segments may be added tothe robotic arm or removed from the robotic arm to change its length.Segments may be added to the robotic arm in order to target scalingdeposits located deeper within a space. Segments may be removed from therobotic arm in cases where increased depth is not needed. In someimplementations, the number of segments that make up the robotic arm maybe based on the length of a pipe to be treated. The robotic arm may beassembled prior to use by connecting multiple segments together usingconnection mechanisms. For example, segments may be screwed together orconnected using clamps, bolts, or screws. The segments areconfigured—for example, constructed or assembled—to bend around contoursof a pipe or other confined space during insertion and removal.

The laser tool may be used to remove scaling from pipes that are locatedunderground. For example, the laser tool may be used to remove scalingfrom metal pipes in a water well or hydrocarbon well. Going forward, ametal pipe (or simply “pipe”) is used as the example object from whichscaling is removed.

As shown in FIG. 1, the laser tool may operate within the interior apipe 29 to be treated using the laser tool. The interior of the pipe isa confined space in that the interior surface of the metal piperestricts movement of the laser tool. The laser tool may be moved intothe pipe using a coiled tubing unit, a wireline, or a tractor. In someimplementations, the laser tool also may be configured to mount to anelongated structure (not shown) that fits within the pipe and thatallows the laser tool to reach scaling deposits that could not bereached with the laser tool alone. In some implementations, theelongated structure having the laser tool attached may be moved into thepipe using the coiled tubing unit, the wireline, or the tractor. In someimplementations, the laser tool can operate at a depth or reach of about2 kilometers (km) depending upon the optical power of the laser beam. Insome implementations, the optical power of the laser beam is between 1kilowatt (kW) and 10 kW.

The laser tool may include one or more stabilizers to secure part of therobotic arm against the interior surface of the pipe. FIG. 1 shows anexample stabilizer 30. Stabilizer 30 includes a holder 31 to containpart 32 of robotic arm 14. The holder is shown in cross-section in thefigures. The holder may include a tube or other hollow structure throughwhich the robotic arm threads. The holder may be made of plastic ormetal and has sufficient rigidity to constrain movement of part 32 ofthe robotic arm. For example, the holder may keep part 32 of the roboticarm centered in the pipe. However, the holder does allow for onedimensional translational (linear) and rotational movement of therobotic arm. Also, while the holder limits movement of part 32 of therobotic arm, it does not limit movement of the part 33 of the roboticarm that positions the laser head to remove the scaling.

Stabilizer 30 also includes arms 35 and 36 that are connected,respectively, to pads 38 and 39. The pads may be mounted pivotally ontheir respective arms to enable at least partial rotation or pivot alongarrow 40. The arms are controllable to expand outward from the holderalong the directions of arrows 41, 42 to the position shown in FIG. 1.This movement forces the pads against the inner surface 43 of pipe 29 inthe example of FIG. 1. The pads may have sufficient pliability toconform to an uneven or nonaligned surface to maximize their surfacecontact. Additionally, the rotation of the pads along arrow 40 promotesmaximal contact to uneven or nonaligned surfaces. The stabilizer thusanchors the robotic arm within pipe 29.

Optical transmission media, such as fiber optic cables 44, deliver thelaser beam from a laser source to laser head 11. In someimplementations, at least part of the fiber optic cables pass through,and are contained within, robotic arm 14. Thus, the fiber optic cablesmay be protected by the structure of the robotic arm. The fiber opticcables extend from the laser head to the laser source. The laser sourceis remote from the laser head. In some implementations, the laser sourceis physically separate from the robotic arm. For example, inimplementations of the laser tool that remove scaling from pipesdownhole in a well, the laser source may be located at a surface abovethe wellbore. In implementations of the laser tool that remove scalingfrom pipes or other confined spaces that are on the surface or notwithin the depths of a well, the laser source may be located outside ofthe pipes or confined spaces. In some implementations, the laser sourcemay be connected to, or mounted on, the robotic arm. For example, thelaser source may be mounted to an end of the robotic arm that isopposite to the end that holds the laser head.

The laser source may include a laser generator. In some implementations,the laser generator is configured to generate a ytterbium multi-cladfiber laser. However, laser generators that generate other types oflasers may be used. Examples of these other types of lasers includeerbium lasers, neodymium lasers, dysprosium lasers, praseodymium lasers,and thulium lasers. The lasers may be pulsed or continuous.

An example laser generator is a direct diode laser. Direct diode lasersinclude laser systems that use the output of laser diodes directly in anapplication. This is in contrast to other types of lasers in which theoutput of laser diodes is used to pump another laser to generate anoutput. Examples of direct diode lasers include systems that generatestraight-line beam shapes. A straight-line beam shape includes lasersthat travel directly from one point to another. A straight-line beamshape also includes lasers beams having a cross-sectional diameter thatstays the same or that changes during travel.

Laser tool 10 may include one or more sensors 47 to sense environmentalconditions in a region where the laser tool operates. For example, ifthe laser tool operates in a pipe within a well, the sensors obtain dataabout environmental conditions within the pipe. The sensors areconfigured to provide data based on the environmental conditions to acontrol system. The control system may use this data to generateinformation about the progress of the tool in removing scaling or thecontrol system may use this data to adjust or cease operation of thetool. Transmission media such as fiber optics or Ethernet may runbetween the sensors and the control system to transmit data from thesensors to the control system or from the control system to the sensors.The transmission media may run along the length of the robotic arm. Insome implementations, data exchange between the sensors and the controlsystem may be implemented wirelessly.

Examples of the environmental sensors may include temperature sensors tomeasure temperature in a region of the tool's operation, pressuresensors to measure pressure in a region of the tool's operation, andvibration sensors to measure vibrations levels in a region of the tool'soperation. The control system may receive signals from one or more ofthese sensors. The signals received from the sensors may indicate thatthere are problems in the region or that there are problems with thelaser tool. An operator may take corrective action based on thesesignals. For example, if a temperature or a pressure is such that thelaser tool may be damaged, the laser tool may be withdrawn. For example,if the laser tool is not operating correctly, it may be withdrawn andadjusted or repaired.

In some implementations, the laser tool may include acoustic sensors forobtaining acoustic data or an acoustic camera for obtaining acousticdata and capturing images or video. The acoustic sensors may be locatedalong the robotic arm or on the laser head. The acoustic camera may belocated along the robotic arm or on the laser head. Data obtained fromthe acoustic sensors or the acoustic camera may be sent to the controlsystem. There, the data may be processed to monitor or to view lasertool operation in real-time. Real-time images or video of the operationof the laser tool may be rendered on a display screen. In this regard,real-time may not mean that two actions are simultaneous, but rather mayinclude actions that occur on a continuous basis or track each other intime, taking into account delays associated with data processing, datatransmission, and hardware.

At the control system, the data also may be processed to determinedownhole conditions. Data captured by the acoustic sensors or acousticcamera may include velocities of sound waves traveled and reflected in aregion where the scaling is located. This information may used todetermine mechanical properties of the scaling including its stability,to evaluate performance of the laser tool, and to control movement ofthe laser tool and troubleshooting of the laser tool. For example, if animage shows that the laser tool is not targeting the scaling, thecontrol system may move the laser tool to change its target. Forexample, if the acoustic data indicates the presence of unexpectedscaling or other material in a pipe, operation of the laser tool may bechanged to account for these conditions. The intensity of the laser beammay be increased in this case. Alternatively or in addition, the patternof impact of the laser beam may be changed. In another example, if theacoustic data indicates that the tool is stuck, actions may be taken tofree the tool.

The control system may include a computing system 45 that is locatedremotely from the laser tool. The computing system may be configured—forexample, programmed—to control operation of the laser tool, to analyzedata from the sensors or acoustic camera, and to output informationbased on the analysis. In implementations of the laser tool that removescaling from pipes downhole in a well, the computing system may belocated at a surface above the wellbore. In implementations of the lasertool that remove scaling from pipes or other confined spaces that are onthe surface or not within the depths of a well, the computing system maybe located outside of the pipes or confined spaces.

Signals may be exchanged between computing system 45 and components ofthe laser tool via wired or wireless connections. In an example,communication media such as Ethernet or other wiring may carry commandsand data to and from the laser tool. The commands may be generated bythe computing system. The commands may control operation of the tool.For example, the commands may include commands to start operation of thelaser tool, to end operation of the laser tool, to change the intensityof the laser beam, to change the shape of the laser beam, or to changethe direction of the laser beam to target a different location. In someimplementations, the commands may instruct movement of the laser head inone, two, three, four, five, or six degrees of freedom. Segments andother components of the robotic arm may include local electronicscapable of receiving and executing operations defined by the commands.Dashed arrow 46 represents communications between the laser tool and thecomputing system.

The control system may include electronics or an on-board computingsystem to implement control over the positioning and operation of thelaser tool. The on-board computing system is “on-board” in the sensethat it is located on the tool itself or downhole with the tool, ratherthan at the surface. The electronics or on-board computing system maycommunicate with computing system 45 to control operation and movementof the laser tool. For example, the on-board computing system maycooperate with computing system 45 to control operation of the lasertool based on sensor readings as described previously. Alternatively,the electronics or on-board computing system may be used instead ofcomputing system 45. For example, the electronics or on-board computingsystem may be configured—for example programmed—prior to operation toimplement control instructions in a sequence during operation absentuser intervention. The on-board computing system may perform all or someof the operations attributed to computing system 45.

Laser tool 10 includes one or more target purging nozzles 49 locatedoutside of laser head 11. The target purging nozzles are configured tooutput a purging medium towards a target of the laser beam. The purgingmedium is output forcefully to the target of the laser beam and isoutput while the laser beam is being applied to the target. The purgingmedium moves debris 12, such as scaling, out of the way of the laserbeam. Arrows 15 depict movement of debris 12 out of the way or the laserbeam and around the robotic arm. The purging medium also may reduce thetemperature of adjacent structures, such as metal pipe. The purgingmedium may be a liquid, a gas, or both a liquid and a gas. For example,the purging medium may include a non-reactive, inert gas such asnitrogen. For example, the purging medium may include a liquid such ashalocarbon. A halocarbon includes a compound, such as achlorofluorocarbon, that incudes carbon combined with one or morehalogens. Examples of halocarbon include halocarbon-oil havingviscosities in a range from 0.8 centipoise (cP) to 1000 cP at 100degrees (°) Fahrenheit (37.8° Celsius). In some implementations, purgingmay be cyclical. For example, purging may occur only while the laserbeam is on.

Laser tool 10 includes one or more head purging nozzles (not shown)located inside of laser head 11. The head purging nozzles are configuredto output a purging medium within the laser head. The head purgingnozzles may output the purging medium forcefully while the laser beam isbeing applied to the target. The output purging medium clears a path forthe laser beam within the head by removing debris and other materialswithin or near the head. The output purging medium also may prevent thedebris and other materials from contaminating the optical assembly.Furthermore, the purging medium is heated by the laser beam within thehead and output from the head with the laser beam. The purging mediummay therefore also assist in removal of debris and other materials froma treatment site. The purging medium may be a liquid, a gas, or both aliquid and a gas. For example, the purging medium may include anon-reactive, inert gas such as nitrogen. For example, the purgingmedium may include a liquid such as halocarbon. In some implementations,purging using the head purging nozzles may be cyclical. For example,purging may occur only while the laser beam is on.

In some implementations, laser tool 10 may include an on-board vacuumsystem to assist in removing debris and other materials from a treatmentsite. An example of a vacuum 50 integrated into laser tool 10 is shownin FIG. 3. In some implementations, the vacuum may operate with asuction force of −15 pounds-per-square-inch gauge (psig) (204.7kilopascal (kPa)). Operation of the vacuum may be controlled by thecontrol system. The vacuum may suction debris and other materials awayfrom the treatment site. In some implementations, tubing (not shown) maytransport the debris or other materials outside of the pipe.

FIG. 4 shows an example process 51 for removing scaling from within ametal pipe using a laser tool, such as laser tool 10. Initially, thelaser tool is assembled (52). The laser tool is assembled by connectinga string of two or more segments in series. The length of the laser toolmay correspond to the location of a site of scaling to be removed by thelaser tool. In some implementations, the length of the laser tool may beone meter. In some implementations, the length of the laser tool may betwo, three, four, five, six, or seven meters depending upon how far thelaser tool needs to reach within the pipe.

The laser tool is mounted (53) to an elongated structure for movementtowards its target. The elongated structure may be a pipe made of metal,composite, or plastic that is configured to bend around contours. Forexample, the elongated structure may be made of a flexible material,such as flexible tubing. This operation may be omitted if the lasertool's target can be reached without the additional length provided bythe elongated structure.

The laser tool—mounted or not to the elongated structure—is moved (54)into the pipe and towards the scaling to be treated. If the pipe islocated downhole of a well, the laser tool may be lowered into thewellbore using a coiled tubing unit, a wireline, or a tractor as noted.The tool may be moved into position by operation of the coiled tubingunit, wireline, or tractor. For example, the tool may be moved throughthe wellbore to reach the entry to the pipe and then enter and movethrough the pipe to the point where the scaling is located. The path maybe determined beforehand based on knowledge about the length of thewellbore, the location of the pipe within the wellbore, and the locationof the scaling within the pipe.

Once near to position, the stabilizer is activated (55) to secure partof the robotic arm of the tool to the inner surface of the pipe. Asexplained, the arms of the stabilizer move outward so that the padsforcefully contact the inner surface of the pipe. In this way, thestabilizer keeps part the robotic arm centered in the pipe. Asexplained, the stabilizer limits movement of part of the robotic arm.However, the stabilizer does allow for translational and rotationalmovement of the robotic arm within and through the stabilizer to enablemovement of the laser head in one or more degrees of freedom to treatthe scaling using a laser beam.

When in position, the robotic arm is controlled (56) to move in one ormore degrees of freedom within the pipe in order to position the laserhead to direct a laser beam to remove the scaling from the pipe. Asexplained, positioning of the robotic arm may be controlled by a controlsystem that is remote from the laser tool or that is on-board the lasertool. Electronics in segments of the robotic arm react to commands fromthe control system to move as instructed. The robotic arm may moveduring application of the laser beam to the scaling. As described, therobotic arm may move in a circular pattern, a spiral pattern, or anirregular pattern

In some implementations, the robotic arm may be controlled to move in upto six degrees of freedom within the metal pipe to target the scalingwith the laser head. As explained with respect to FIG. 2, the sixdegrees of freedom include: forward and backward motion on the X-axis,left and right motion on the Y-axis, up and down motion on the Z-axis,side-to-side tilting over the X-axis, forward and backward tilting overthe Y-axis, and left and right tilting over the Z-axis. The robotic armmay be controlled to move in any one of the preceding degrees offreedom, in any two of the preceding degrees of freedom, in any three ofthe preceding degrees of freedom, in any four of the preceding degreesof freedom, in any five of the preceding degrees of freedom, or in sixof the preceding degrees of freedom. For example, linear movementtowards or away from the scaling along the X-axis alone is movement inone degree of freedom. In another example, circular movement around theX-axis coupled with X-axis linear movement towards or away from thescaling is movement in two degrees of freedom. In another example,linear movement through the X, Y, and Z dimensions is movement in threedegrees of freedom. In another example, movement through the X, Y, and Zdimensions having an angular component around the Y-axis is movement infour degrees of freedom. In another example, movement through the X, Y,and Z dimensions having angular components around the Y-axis and theZ-axis is movement in five degrees of freedom. Movement through the X,Y, and Z dimensions having angular components around the X-axis, theY-axis, and the Z-axis is movement in six degrees of freedom. Followingtreatment of the scaling, the laser tool may be withdrawn (57).

FIGS. 1 and 3 show laser tool 10 applying a laser beam directly toscaling 60 to remove the scaling blocking pipe 29. FIG. 5 shows usinglaser tool 10 applying laser beam 62 to pipe 29 itself, rather than toscaling 63. This causes the pipe to increase in temperature—for example,up to 150 degrees (°) Celsius (C). This may also result in removal ofthe scaling for the following reasons. The metal that comprises the pipeheats by application of the laser beam. This heating causes the metal toexpand. The scale will experience some heating as well, but will expandat a different rate than the metal. The difference in expansion rates ofthe metal and the scaling causes the scaling to peel away from the pipe.The scaling may then be carried away by purging media or vacuum. Thistype of removal may be particularly effective where scaling coats,rather than blocks, a pipe.

As noted, after the scaling has been removed, the laser tool may beextracted from the pipe using the coiled tubing unit, the wireline, orthe tractor. In cases where the laser tool is operating downhole withina well, the laser tool is also be brought uphole.

Examples of scaling that may be removed using the laser tool includescalcite, aragonite, vaterite, anhydrite, gypsum, barite, celestite,mackinawite (iron sulfide), pyrite, halite, fluorite, sphaerite, andgalena.

Examples of other objects from which the laser tool may remove scalinginclude casings, tubing, valves, pumps, downhole completion tools,sub-surface safety valves, screens, gravel packs, and perforations.

All or part of the tools and processes described in this specificationand their various modifications may be controlled at least in part by acontrol system comprised of one or more computing systems using one ormore computer programs. Examples of computing systems include, eitheralone or in combination, one or more desktop computers, laptopcomputers, servers, server farms, and mobile computing devices such assmartphones, features phones, and tablet computers.

The computer programs may be tangibly embodied in one or moreinformation carriers, such as in one or more non-transitorymachine-readable storage media. A computer program can be written in anyform of programming language, including compiled or interpretedlanguages, and it can be deployed as a stand-alone program or as amodule, part, subroutine, or unit suitable for use in a computingenvironment. A computer program can be deployed to be executed on onecomputer system or on multiple computer systems at one site ordistributed across multiple sites and interconnected by a network.

Actions associated with implementing the processes may be performed byone or more programmable processors executing one or more computerprograms. All or part of the tools and processes may include specialpurpose logic circuitry, for example, an field programmable gate array(FPGA) or an ASIC application-specific integrated circuit (ASIC), orboth.

Processors suitable for the execution of a computer program include, forexample, both general and special purpose microprocessors, and includeany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only storagearea or a random access storage area, or both. Components of a computer(including a server) include one or more processors for executinginstructions and one or more storage area devices for storinginstructions and data. Generally, a computer will also include one ormore machine-readable storage media, or will be operatively coupled toreceive data from, or transfer data to, or both, one or moremachine-readable storage media.

Non-transitory machine-readable storage media include mass storagedevices for storing data, for example, magnetic, magneto-optical disks,or optical disks. Non-transitory machine-readable storage media suitablefor embodying computer program instructions and data include all formsof non-volatile storage area. Non-transitory machine-readable storagemedia include, for example, semiconductor storage area devices, forexample, erasable programmable read-only memory (EPROM), electricallyerasable programmable read-only memory (EEPROM), and flash storage areadevices. Non-transitory machine-readable storage media include, forexample, magnetic disks such as internal hard disks or removable disks,magneto-optical disks, and CD (compact disc) ROM (read only memory) andDVD (digital versatile disk) ROM.

Each computing device may include a hard drive for storing data andcomputer programs, one or more processing devices (for example, amicroprocessor), and memory (for example, RAM) for executing computerprograms. Each computing device may include an image capture device,such as a still camera or video camera. The image capture device may bebuilt-in or simply accessible to the computing device.

Elements of different implementations described may be combined to formother implementations not specifically set forth previously. Elementsmay be left out of the tools and processes described without adverselyaffecting their operation or operation of the overall system in general.Furthermore, various separate elements may be combined into one or moreindividual elements to perform the functions described in thisspecification.

Other implementations not specifically described in this specificationare also within the scope of the following claims.

What is claimed is:
 1. A method of removing scaling from an objectwithin a confined space using a laser tool comprised of a robotic armand a laser head connected to the robotic arm to output a laser beam,the method comprising: moving the laser tool into the confined space;and controlling the robotic arm to move in at least three degrees offreedom within the confined space in order to direct a laser beam toremove the scaling from the object.
 2. The method of claim 1, wherecontrolling the robotic arm comprises controlling the robotic arm tomove in at least six degrees of freedom.
 3. The method of claim 1, wherecontrolling the robotic arm comprises sending at least one command froma control system to electronics located in segments of the robotic arm.4. The method of claim 1, where the object comprises at least one of apump, a sub-surface safety valve, a screen, and a gravel pack.
 5. Themethod of claim 1, where directing the laser beam for removal of thescaling comprises pointing the laser beam at the scaling.
 6. The methodof claim 1, where directing the laser beam for removal of the scalingcomprises pointing the laser beam at a surface of the object adjacent tothe scaling.
 7. The method of claim 1, where the scaling removed fromthe object is suctioned away from the laser head using a vacuum.
 8. Themethod of claim 1, where controlling the robotic arm comprises movingthe robotic arm in a spiral pattern.
 9. The method of claim 1, wherecontrolling the robotic arm comprises moving the robotic arm in acircular pattern.
 10. The method of claim 1, further comprising:outputting a purging medium towards the scaling during removal of thescaling by the laser tool.
 11. The method of claim 1, furthercomprising: monitoring environmental conditions within the confinedspace during removal of the scaling by the laser tool; where controlover the robotic arm is based, at least in part, on the environmentalconditions.
 12. The method of claim 11, where the environmentalconditions comprise one or more a temperature within the confined space,pressure within the confined space, or sound within the confined space.13. The method of claim 11, further comprising: securing at least partof the robotic arm against the object during removal of the scaling. 14.The method of claim 13, where the at least part of the robotic arm iscentered within the confined space during removal of the scaling, 15.The method of claim 1, where an optical power of the laser beam isbetween 1 kilowatt (kW) and 10 kW.
 16. The method of claim 1, furthercomprising: shaping the laser beam prior to output, where shaping thelaser beam comprises at least one of focusing the laser beam,collimating the laser beam, or dispersing the laser beam.
 17. The methodof claim 1, where the object is a metal pipe; and where the confinedspace is an interior of the metal pipe.
 18. The method of claim 1,further comprising assembling the laser tool prior to moving the lasertool, wherein the laser tool comprises a length in a range from about 1meter to about 7 meters.
 19. The method of claim 1, further comprisingactivating a stabilizer to secure part of the robotic arm of the lasertool to an inner surface of the confined space.
 20. The method of claim19, further comprising: rotating the rotating the robotic arm within thestabilizer; and translating the robotic arm through the stabilizer.